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logos2
07-13-2001, 02:18 PM
I was looking at a very old machine shop textbook at a section on cutting helical gears. Some time later I saw a machine tool sale paper at the place where I get metal for my home shop. In the paper they had a China made mill like in the old textbook. Next time I was back there I ask about the tool sales paper the man running shop sad it was just a random paper and did not know thir name. Can anyone help me locate one of this type of machine. I would like to try to do a helical gear. If there is a way to set up bridgeport to do this that would work for me too.

halfnut
07-14-2001, 06:43 AM
Helical gears are generally cut with a hobbing machine, rather expensive rascal, tooling also, Barber Coleman most common.

Cutting helical gears on a mill is done on a horizontal universal. The table will swivel to the helix angle of the gear. A differential dividing head is also required, this is geared to the table lead screw. Of course you have to have right gearing.

I have thought about the helical gears and Bridgeports. I think it can be done by swiveling the head to the helix angle. The real trick will be gearing the leadscrew to the dividing head. Don't know why it won't work myself, seen lots of wild things done on a bridgeport, but not this.

Story, went into local shop one day, fellow was cutting 10 foot radius on Bridgeport clone. Had Y screw disconnected, a ten foot link mounted to table, and anchored to a small horizontal on the other end. He was advancing cutter with the ram using a dial indicator. Worked the best.

logos2
07-15-2001, 01:20 PM
Halfnut
Thanks for reply. I send all the gear work at work to a place in S.C. They have C.N.C. gear cutters it has become a specility feild I guess. We had two hobbs at work I sold them last year to a place that retrofitts hobbs. What I am looking to do is just for fun. If I do not work at home on manual machines I am afraid I will loose touch. At work all I do is CNC and paper work. Bummer!
If I could find mill would try to buy cut a paiir of gears.
Thanks again
Roger

<font face="Verdana, Arial" size="2">Originally posted by halfnut:
Helical gears are generally cut with a hobbing machine, rather expensive rascal, tooling also, Barber Coleman most common.

Cutting helical gears on a mill is done on a horizontal universal. The table will swivel to the helix angle of the gear. A differential dividing head is also required, this is geared to the table lead screw. Of course you have to have right gearing.

I have thought about the helical gears and Bridgeports. I think it can be done by swiveling the head to the helix angle. The real trick will be gearing the leadscrew to the dividing head. Don't know why it won't work myself, seen lots of wild things done on a bridgeport, but not this.

Story, went into local shop one day, fellow was cutting 10 foot radius on Bridgeport clone. Had Y screw disconnected, a ten foot link mounted to table, and anchored to a small horizontal on the other end. He was advancing cutter with the ram using a dial indicator. Worked the best.

</font>

SGW
07-22-2001, 08:29 AM
Try the book "Gears and Gear Cutting" by Ivan Law. It gives a lot of information about how to do gear cutting in a home shop without all the fancy commercial equipment. I can't remember offhand if it talks about helical gears, but I know it does explain how to do bevel gears, which of course are also quite a challenge.

Ironman
07-31-2001, 01:30 AM
Book-"A Treatise On Milling"by Cinncinati
Milling Machine Co.Most excellent treatment of gear making on mills.Also lots of unusual setups,eg,grinding cams on a mill!